Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare destructiveHint=true and openWorldHint=true, so the description does not need to re-establish that this is a mutation. It adds useful context by explaining that templates can affect publishing flows and by calling out the confirmation requirements tied to that impact. It stops short of explaining replacement behavior for an existing default or other operational details.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two sentences, front-loads the core action and scope, and then states the confirmation requirements and their rationale. There is no redundant filler or unnecessary background.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a destructive mutation with rich annotations, a complete schema, and an output schema, the description supplies the key context an agent needs: scope, confirmation gates, and publishing-flow impact. It could be slightly fuller by explicitly noting that making a template default replaces the existing default, but the current text is largely sufficient.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the input schema already documents each parameter. The description reinforces the rationale for confirmed and impactConfirmed and mentions ChannelOAuthId resolution, but it does not add much parameter meaning beyond what the schema provides.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb and resource: it 'Marks a listing template as default' and scopes this to 'one visible store/channel'. That is clear enough for an agent to identify the operation, though it does not explicitly distinguish it from sibling tools such as hgr_update_template.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives prerequisite context by requiring confirmed=true and impactConfirmed=true because templates can affect publishing flows. However, it does not say when to use this tool versus alternatives like hgr_update_template or hgr_list_templates, and it provides no exclusions or alternative-routing guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.